if its the aluminum dome tweeter then i believe that this is the one
https://www.falconacoustics.co.uk/seas-h0623-06-25tafn-qg-tweeter-meridian-dsp420-tweeter.html

can you swap the tweeters round to check? could be a ferrofluid issue but at the price of the tweeters I would buy new.

Rgds
Stuart

Linn LP12, Ittok LV11, Arkiv, Linn Kairn as a phono stage, MPmax 221, DSP6000's, WiiM Pro streamer.